4 × 1km
Source: own Strava export
A 2 km/1 km benchmark set was built around consistently hard running, with static recoveries separating the longer efforts and the shorter repetitions. The grass and sun added load, while the limited recoveries made repeatability more important than a maximal opening effort.
The 2 km efforts ran at 3:30/km and 3:33/km, then the 1 km repetitions faded from 3:27/km to 3:40/km. Heart rate was 179 and 182 for the longer efforts, then 175, 178, 175 and 176 for the shorter ones, showing a clear pace fade without a corresponding late heart-rate rise.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:27 | 3:27/km | 175 | 1:00 |
| 2 | 3:31 | 3:31/km | 178 | 1:00 |
| 3 | 3:36 | 3:36/km | 175 | 1:00 |
| 4 | 3:40 | 3:40/km | 176 | 1:00 |
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 60s.
Calibration flags
- Running power threshold estimated from the athlete's half-marathon best efforts (60-min power 476 W, 95% of 20-min power 460 W). Treat power zones and load as ±3%.
- Zones and running threshold are one snapshot, read 2 Jul 2026 and applied to every session in the archive. An older session is scored against today's zones, not the zones the athlete trained with then.
Engine read · editorial decode by Splits
Time in zone
The rep pace re-expressed for flat ground and cool air, the effort, not the clock. The gap between actual and true effort is the day's hidden work: conditions were taxing the clock.